Methods of Herbicide Application

Herbicides can be applied in various ways, depending on the type of crop, weed species, and the formulation of the herbicide. Proper application ensures maximum efficacy and minimal crop damage.

a. Soil Application (Pre-Emergence)

• Applied to the soil before weed or crop emergence.
• Works by preventing weed seed germination or killing young seedlings.
• Examples: Butachlor in rice, Atrazine in maize.
• Method: Spray evenly on soil surface and incorporate by light tillage or irrigation if required.

b. Foliar Application (Post-Emergence)

• Applied directly to the leaves and shoots of actively growing weeds.
• Contact herbicides kill only the parts they touch, while systemic herbicides move inside the plant to roots and rhizomes.
• Examples: 2,4-D, Glyphosate, Paraquat.
• Method: Sprayed using knapsack sprayers, boom sprayers, or aerial spraying in large areas.

c. Directed or Spot Application

• Herbicide applied directly on weeds only, avoiding crop contact.
• Used for perennial weeds, large weeds, or field edges.
• Advantages: Reduces herbicide use and avoids crop damage.

d. Stubble or Fallow Application

• Applied on post-harvest fields or fallow land to control weeds before the next crop.
• Common for non-selective herbicides like Glyphosate and Paraquat.
• Purpose: Reduces weed seed bank and prevents early weed establishment in the next crop.

e. Seed Dressing / Pre-Planting Treatment

• Herbicide applied to seeds before sowing to protect crops from early weed competition.
• Examples: Certain pre-emergence herbicides used in maize, wheat, or legumes.

f. Granular Application

• Herbicide applied in granular form, either broadcast or banded along rows.
• Often used in paddy fields or vegetable crops.
• Advantages: Uniform distribution and reduced drift compared to liquid sprays.

g. Aerial Application

• Spraying herbicides from aircraft or drones in large or inaccessible areas.
• Mainly used in forestry, large-scale rice, maize, or sugarcane fields.
• Advantages: Quick coverage, but requires wind and weather control to avoid drift.